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mvdata.go
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mvdata.go
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package block_stm
import (
"bytes"
storetypes "cosmossdk.io/store/types"
)
const (
// Since we do copy-on-write a lot, smaller degree means smaller allocations
OuterBTreeDegree = 4
InnerBTreeDegree = 4
)
type MVData = GMVData[[]byte]
func NewMVData() *MVData {
return NewGMVData(BytesIsZero, BytesLen)
}
type GMVData[V any] struct {
BTree[dataItem[V]]
isZero func(V) bool
valueLen func(V) int
}
func NewMVStore(key storetypes.StoreKey) MVStore {
switch key.(type) {
case *storetypes.ObjectStoreKey:
return NewGMVData(ObjIsZero, ObjLen)
default:
return NewGMVData(BytesIsZero, BytesLen)
}
}
func NewGMVData[V any](isZero func(V) bool, valueLen func(V) int) *GMVData[V] {
return &GMVData[V]{
BTree: *NewBTree(KeyItemLess[dataItem[V]], OuterBTreeDegree),
isZero: isZero,
valueLen: valueLen,
}
}
// getTree returns `nil` if not found
func (d *GMVData[V]) getTree(key Key) *BTree[secondaryDataItem[V]] {
outer, _ := d.Get(dataItem[V]{Key: key})
return outer.Tree
}
// getTreeOrDefault set a new tree atomically if not found.
func (d *GMVData[V]) getTreeOrDefault(key Key) *BTree[secondaryDataItem[V]] {
return d.GetOrDefault(dataItem[V]{Key: key}, func(item *dataItem[V]) {
if item.Tree == nil {
item.Tree = NewBTree(secondaryLesser[V], InnerBTreeDegree)
}
}).Tree
}
func (d *GMVData[V]) Write(key Key, value V, version TxnVersion) {
tree := d.getTreeOrDefault(key)
tree.Set(secondaryDataItem[V]{Index: version.Index, Incarnation: version.Incarnation, Value: value})
}
func (d *GMVData[V]) WriteEstimate(key Key, txn TxnIndex) {
tree := d.getTreeOrDefault(key)
tree.Set(secondaryDataItem[V]{Index: txn, Estimate: true})
}
func (d *GMVData[V]) Delete(key Key, txn TxnIndex) {
tree := d.getTreeOrDefault(key)
tree.Delete(secondaryDataItem[V]{Index: txn})
}
// Read returns the value and the version of the value that's less than the given txn.
// If the key is not found, returns `(nil, InvalidTxnVersion, false)`.
// If the key is found but value is an estimate, returns `(nil, BlockingTxn, true)`.
// If the key is found, returns `(value, version, false)`, `value` can be `nil` which means deleted.
func (d *GMVData[V]) Read(key Key, txn TxnIndex) (V, TxnVersion, bool) {
var zero V
if txn == 0 {
return zero, InvalidTxnVersion, false
}
tree := d.getTree(key)
if tree == nil {
return zero, InvalidTxnVersion, false
}
// find the closing txn that's less than the given txn
item, ok := seekClosestTxn(tree, txn)
if !ok {
return zero, InvalidTxnVersion, false
}
return item.Value, item.Version(), item.Estimate
}
func (d *GMVData[V]) Iterator(
opts IteratorOptions, txn TxnIndex,
waitFn func(TxnIndex),
) *MVIterator[V] {
return NewMVIterator(opts, txn, d.Iter(), waitFn)
}
// ValidateReadSet validates the read descriptors,
// returns true if valid.
func (d *GMVData[V]) ValidateReadSet(txn TxnIndex, rs *ReadSet) bool {
for _, desc := range rs.Reads {
_, version, estimate := d.Read(desc.Key, txn)
if estimate {
// previously read entry from data, now ESTIMATE
return false
}
if version != desc.Version {
// previously read entry from data, now NOT_FOUND,
// or read some entry, but not the same version as before
return false
}
}
for _, desc := range rs.Iterators {
if !d.validateIterator(desc, txn) {
return false
}
}
return true
}
// validateIterator validates the iteration descriptor by replaying and compare the recorded reads.
// returns true if valid.
func (d *GMVData[V]) validateIterator(desc IteratorDescriptor, txn TxnIndex) bool {
it := NewMVIterator(desc.IteratorOptions, txn, d.Iter(), nil)
defer it.Close()
var i int
for ; it.Valid(); it.Next() {
if desc.Stop != nil {
if BytesBeyond(it.Key(), desc.Stop, desc.Ascending) {
break
}
}
if i >= len(desc.Reads) {
return false
}
read := desc.Reads[i]
if read.Version != it.Version() || !bytes.Equal(read.Key, it.Key()) {
return false
}
i++
}
// we read an estimate value, fail the validation.
if it.ReadEstimateValue() {
return false
}
return i == len(desc.Reads)
}
func (d *GMVData[V]) Snapshot() (snapshot []GKVPair[V]) {
d.SnapshotTo(func(key Key, value V) bool {
snapshot = append(snapshot, GKVPair[V]{key, value})
return true
})
return
}
func (d *GMVData[V]) SnapshotTo(cb func(Key, V) bool) {
d.Scan(func(outer dataItem[V]) bool {
item, ok := outer.Tree.Max()
if !ok {
return true
}
if item.Estimate {
return true
}
return cb(outer.Key, item.Value)
})
}
func (d *GMVData[V]) SnapshotToStore(store storetypes.Store) {
kv := store.(storetypes.GKVStore[V])
d.SnapshotTo(func(key Key, value V) bool {
if d.isZero(value) {
kv.Delete(key)
} else {
kv.Set(key, value)
}
return true
})
}
type GKVPair[V any] struct {
Key Key
Value V
}
type KVPair = GKVPair[[]byte]
type dataItem[V any] struct {
Key Key
Tree *BTree[secondaryDataItem[V]]
}
var _ KeyItem = dataItem[[]byte]{}
func (item dataItem[V]) GetKey() []byte {
return item.Key
}
type secondaryDataItem[V any] struct {
Index TxnIndex
Incarnation Incarnation
Value V
Estimate bool
}
func secondaryLesser[V any](a, b secondaryDataItem[V]) bool {
return a.Index < b.Index
}
func (item secondaryDataItem[V]) Version() TxnVersion {
return TxnVersion{Index: item.Index, Incarnation: item.Incarnation}
}
// seekClosestTxn returns the closest txn that's less than the given txn.
func seekClosestTxn[V any](tree *BTree[secondaryDataItem[V]], txn TxnIndex) (secondaryDataItem[V], bool) {
return tree.ReverseSeek(secondaryDataItem[V]{Index: txn - 1})
}